weight gain and weight loss

Hello I have been losing weight lately without dieting, lost 20 lbs, Also have loss of appetite. Besides that all is fine. Don’t feel any weakness. No extra stress or exercise. No pain. Nothing. What can be the problem?

I’m 29 yrs. / female. I’ve troubles with my cholesterol levels and my weight. the problem started after I took these medicines (eltroxin 50 mcg,deltavit b12,inegy 10/20) for only one month starting from 1st June 2016, I gained 25 kg in 16 months even I work out three times a week and my eating habits never changed. I attached my blood tests history before and after the medicines.

Age: 29
Female
Medications: eltroxin 50 mcg,deltavit b12,inegy 10/20, now I’m just taking Omega-3
General Information: 4/12/2017 I had a pelvi-abdominal sonography only comment was “fatty liver”, Sometimes I’ve slight pain in my waist (right side). I experience pain in my feet (lower back) when I wake up in the morning, it disappears after couple of minutes.

My wife is 5″8-9″ weighs 110lbs
I want to put her on a weight gainer supplement. It helped her 14 years when she had a similar problem. But she also takes iron pills for her anemia “feramax 150mg” so my question is can I still give her a weight gainer supplement if it has 10% or 14% iron, without harm. If yes is their a maximum % or mg? Thank you